Methods and apparatus for DC-DC converter having dithered slope compensation

Abstract

Methods and apparatus for a circuit including a DC-DC converter including: a boost converter to provide a DC voltage output from a DC input voltage, the DC output voltage configured to connect with a first load terminal, a feedback module configured to connect with a second load terminal, a switching module having a switching element coupled to the boost converter, and a control circuit coupled to the switching module to control operation of the switching element, the control circuit coupled to the feedback module, wherein the control circuit includes a slope generator to generate a ramp signal having a slope that can vary cycle to cycle.

What is claimed is:  
     
       1. A circuit, comprising:
 a DC-DC converter comprising: 
 a boost converter to provide a DC voltage output from a DC input voltage, the DC output voltage configured to connect with a first load terminal; 
 a feedback module configured to connect with a second load terminal; 
 a switching module having a switching element coupled to the boost converter; and 
 a control circuit coupled to the feedback module and to the switching module to generate a control signal to control operation of the switching element for a single mode of operation of the switching element, wherein the control circuit includes a slope generator to generate a ramp signal having a slope that varies cycle to cycle, wherein the ramp signal is initiated by a non-periodic clock signal that varies cycle-to-cycle, such that the control signal for the switching element corresponds to the ramp signal, wherein the switching element has a duty cycle that varies cycle to cycle and a duty cycle on-time that varies cycle to cycle. 
 
     
     
       2. The circuit according to  claim 1 , wherein the DC-DC converter comprises a voltage-mode converter. 
     
     
       3. The circuit according to  claim 1 , wherein the DC-DC converter comprises a current-mode converter. 
     
     
       4. The circuit according to  claim 1 , wherein the control circuit includes a pulse-width modulation circuit. 
     
     
       5. The circuit according to  claim 1 , wherein the control circuit includes a comparator having an output coupled to the switching element. 
     
     
       6. The circuit according to  claim 5 , wherein the comparator is configured to receive the ramp signal. 
     
     
       7. The circuit according to  claim 1 , wherein the control circuit includes a current source to determine the slope of the ramp signal. 
     
     
       8. The circuit according to  claim 7 , wherein the control circuit includes a capacitor that is charged by the current source. 
     
     
       9. The circuit according to  claim 8 , wherein the capacitor discharges upon reaching a first voltage level. 
     
     
       10. The circuit according to  claim 1 , wherein a conversion range of the DC-DC converter is set by a maximum and minimum controllable duty cycle. 
     
     
       11. A method, comprising: employing a DC-DC converter having a boost converter to provide a DC voltage output from a DC input voltage, the DC output voltage configured to connect with a first load terminal; employing a feedback module to connect with a second load terminal; employing a switching module having a switching element coupled to the boost converter; employing a control circuit coupled to the feedback module and to the switching module to control operation of the switching element for a single mode of operation of the switching element; generating a ramp signal in the control circuit, the ramp signal having a slope that varies cycle to cycle, wherein the ramp signal is initiated by a non-periodic clock signal that varies cycle-to-cycle, such that the control signal for the switching element corresponds to the ramp signal, wherein the switching element has a duty cycle that varies cycle to cycle and a duty cycle on-time that varies cycle to cycle. 
     
     
       12. The method according to  claim 11 , wherein the DC-DC converter comprises a voltage-mode converter. 
     
     
       13. The method according to  claim 11 , wherein the DC-DC converter comprises a current-mode converter. 
     
     
       14. The method according to  claim 11 , wherein the control circuit includes a pulse-width modulation circuit. 
     
     
       15. The method according to  claim 11 , wherein the control circuit includes a comparator having an output coupled to the switching element. 
     
     
       16. The method according to  claim 15 , wherein the comparator is configured to receive the ramp signal. 
     
     
       17. The method according to  claim 15 , wherein the control circuit includes a current source to determine the slope of the ramp signal. 
     
     
       18. The method according to  claim 17 , wherein the control circuit includes a capacitor that is charged by the current source. 
     
     
       19. The method according to  claim 18 , wherein the capacitor discharges upon reaching a first voltage level. 
     
     
       20. The method according to  claim 11 , wherein a conversion range of the DC-DC converter is set by a maximum and minimum controllable duty cycle. 
     
     
       21. A circuit, comprising: a DC output voltage configured to connect with a first load terminal; a feedback module configured to connect with a second load terminal; a switching module having a switching element; and a control circuit coupled to the feedback module and to the switching module to generate a control signal to control operation of the switching element for a single mode of operation of the switching element, wherein the control circuit includes a slope generator to generate a ramp signal having a slope that varies cycle to cycle, wherein the ramp signal is initiated by a non-periodic clock signal that varies cycle-to-cycle, such that the control signal for the switching element corresponds to the ramp signal, wherein the switching element has a duty cycle that varies cycle to cycle and a duty cycle on-time that varies cycle to cycle for adjusting switching frequency based on current level.